Variability in salt tolerance of native populations of Elymus scabrifolius

Elymus scabrifolius is a native C3 South American grass species. It is valued as forage species adapted to various environments in Argentina and is also a potential source of traits for wheat-breeding programmes. Efficient utilization of native genetic resources requires extensive collection and characterization of available material. The purpose of this study was to identify and characterize variability in salt tolerance within E. scabrifolius populations in Argentina. Specimens of E. scabrifolius were collected from a wide range of soils in Argentina, and most populations were found in saline environments with high sodium levels. Intraspecific variability in salt tolerance was estimated, and its relation to the salinity level of the populations' natural environment was assessed. A principal component analysis based on growth data distinguished lines from saline and non-saline habitats only under salt conditions. Results suggest that selecting under stressed environments is a reasonable strategy for breeding E. scabrifolius. Lines of saline origin had higher biomass under both control and saline conditions, suggesting that higher gains from selection would be obtained if germplasm from this origin was used, and tillering may be the most useful indirect selection criterion for improving salt tolerance. The association between salt tolerance, ion content and osmotic adjustment was also assessed. Salt-sensitive lines accumulated high sodium levels in leaves. However, osmotic adjustment did not correlate with the maintenance of leaf elongation rates under salinity in the genotypes included in this study.Fil: Zabala, Juan Marcelo. Universidad Nacional del Litoral; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; ArgentinaFil: Taleisnik, Edith. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Fitopatología y Fisiología Vegetal; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Giavedoni, J. A.. Universidad Nacional del Litoral; ArgentinaFil: Pensiero, Jose Francisco. Universidad Nacional del Litoral; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; ArgentinaFil: Schrauf, Gustavo Enrique. Universidad de Buenos Aires. Facultad de Agronomía; Argentin

The austral cordgrass Spartina densiflora Brong.: its taxonomy, biogeography and natural history

Aim  During the last 20 years, the austral cordgrass Spartina densiflora has been recorded aggressively invading estuarine environments in the USA, Spain and Morocco. Whereas this species is one of the three most widely distributed worldwide, it is among the least studied within the genus. The objective of this work is to integrate baseline information about the taxonomy, global distribution, centre of origin, and general ecology of S. densiflora in native and invaded marshes worldwide in order to help to strengthen management efforts currently directed at controlling or eradicating it from locations where it has been introduced.Fil: Bortolus, Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico; Argentin

Sinopse das espécies nativas e subespontâneas de Andropogoneae Dumort. (Poaceae) na Ilha de Santa Catarina, Brasil A synopsis of the Andropogoneae Dumort. (Poaceae) native and subspontaneous to the Island of Santa Catarina, Florianópolis, SC, Brazil

O presente trabalho consiste no levantamento dos táxons da tribo Andropogoneae (Panicoideae - Poaceae) ocorrentes na Ilha de Santa Catarina, Florianópolis, Brasil. A partir da revisão de materiais de herbários e coletas a campo foi confirmada a ocorrência de 10 gêneros e 20 espécies, 17 nativas e duas subespontâneas: Andropogon L. (7 spp.), Bothriochloa Kuntze (2), Eriochrysis P. Beauv. (1), Hyparrhenia Andersson ex E. Fourn. (1), Imperata Cirillo (1), Ischaemum L. (1), Rhytachne Desv. (1), Saccharum L. (3), Schizachyrium Nees (2) e Sorghum Moench (1). Os gêneros Bothriochloa e Rhytachne são registrados pela primeira vez para a Ilha de Santa Catarina. São apresentadas chaves de identificação para gêneros e espécies, ilustrações, informações sobre distribuição geográfica, habitat, período de floração e comentários para cada táxon.<br>The present work is a survey of the taxa in the tribe Andropogoneae (Panicoideae - Poaceae) that occur on the Island of Santa Catarina, Florianópolis, Brazil. Based on a review of herbarium specimens and fieldwork, 20 species were recorded in the following 10 genera: Andropogon L. (7 spp.), Bothriochloa Kuntze (2), Eriochrysis P. Beauv. (1), Hyparrhenia Andersson ex E. Fourn. (1), Imperata Cirillo (1), Ischaemum L. (1), Rhytachne Desv. (1), Saccharum L. (3), Schizachyrium Nees (2) and Sorghum Moench (1). Seventeen of the species are native, and two species are subspontaneous. Bothriochloa and Rhytachne are recorded here, for the first time, for the Island of Santa Catarina. This work provides key to the genera and species, as well as illustrations, information about geographic distribution, habitat, phenology, and comments about each taxon presented in the study

A systematic survey of floral nectaries

The construction of classifications, as well as the understanding of biological diversity, depends upon a careful comparison of attributes of the organisms studied (Stuessy, 1990). It is widely known that data from diverse sources showing differences from taxon to taxon are of systematic significance. Dur-ing the 20th century, systematists have emphasized that their discipline involves a synthesis of all knowledge (Stevens, 1994) or, in other words, the variation of as many relevant characters as possible should be incorporated into the natural system to be constructed. The extent to which particular characters are constant or labile will determine their usefulness to syste-matics. In general, more conservative characters will be valuable in defining families and orders, whereas more labile characters may be useful at the ge-neric and specific levels (Webb, 1984). There is no doubt that floral characters are among the most used in the classification of flowering plants. At the same time, they constitute essential features in diagnostic keys to taxa in both taxonomic treatments and Floras (Cronquist, 1981, 1988).Fil: Bernardello, Gabriel Luis Mario. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentin